# AprilTag — Fast visual-fiducial detection

> 2D barcode detector for robotics and AR, with UDP broadcasting. (iPhone/iPad app by Edwin Olson.)

- Source: https://appshunter.io/ios/app/apriltag/id736108128 (this page in markdown: same URL + `.md`)
- Developer: [Edwin Olson](https://appshunter.io/developer/736108131)
- Category: Utilities
- Price: Free
- Rating: 3.60/5 from 9 App Store ratings · 4 written reviews indexed
- Age rating: 4+
- Requires: iOS 12.0 · 5 MB
- Languages: American English
- Released: 2013-11-20
- Data updated: 2026-06-03
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/apriltag/id736108128/reviews.md

## What is AprilTag?

AprilTags are 2D barcodes designed to be quickly and accurately detected, and are used in a variety of robotics and augmented reality applications. This application is an AprilTag detector that can be used in stand-alone mode, or can broadcast any tags that it detects to another machine via UDP.

With this application, your iPhone is turned into a self-contained and turn-key robot tracking system.

## Key features

- Fast and accurate 2D barcode detection
- Stand-alone detection mode
- UDP broadcasting of detected tags
- Robot tracking system functionality
- Augmented reality applications

## Recent user reviews (4 of 4)

All indexed reviews: https://appshunter.io/ios/app/apriltag/id736108128/reviews.md

### 4/5 — Camera intrinsics?

*2025-05-25*

This is a very useful app, and I am able to capture the packets that it produces on UDP, however, it is not clear what to do with that data?  The author doesn’t specify which resolution he uses, so calculating camera intrinsics becomes a guess work.  Camera data for iPhone is well known, so it would be good to provide camera intrinsics inside the app.

### 1/5 — Simply does not work.

*2022-11-06*

The software is unable to identify tags under any conditions.

### 3/5 — I think it’s really cool and has good potential but...

*2020-01-19*

How do we use udp, also how do we make it do autofocus?

### 2/5 — Great concept but crashes

*2019-02-21*

When I open the app on my iPhone X I just see a black screen. No camera input. Always crashes. Would love to see this working.

## Frequently asked questions about AprilTag

### What is AprilTag used for?

AprilTag is used for fast and accurate detection of 2D barcodes, primarily in robotics and augmented reality applications. It can function as a standalone detector or broadcast tag information to other machines.

### Can AprilTag be used offline?

Yes, AprilTag can be used in stand-alone mode for detecting tags without needing an internet connection. It also offers UDP broadcasting for sending detected tag data to another machine.

### What devices support AprilTag?

AprilTag is supported on iPhone, iPad, and iPod devices. It transforms these devices into a self-contained robot tracking system.

### How often is AprilTag updated?

The latest version of AprilTag is 3.0, which was last updated on March 31, 2019. While it has not been updated recently, it remains a functional utility for its intended purpose.

### What is the age rating for AprilTag?

AprilTag has an age rating of 4+. This indicates it is suitable for users aged 4 and above.

### Does AprilTag have ads?

No, AprilTag does not contain advertisements. It is a free application with no in-app purchases or ads.

### What is the user sentiment for AprilTag based on ratings?

AprilTag has an average rating of 3.6 stars from 9 ratings. This suggests a mixed but generally positive user reception for its functionality.

### Is AprilTag suitable for beginners in robotics?

AprilTag is designed for robotics and AR applications, which can be complex fields. While it provides a turn-key tracking system, users may benefit from prior knowledge in these areas to fully leverage its capabilities.

## Version history (last 3 releases)

### 3.0 — 2019-03-31

* Numerous bug and reliability fixes
* Updated to newest AprilTag detector, including new tag families.

### 2.1.2 — 2014-10-30

This version features improved iOS 8 compatibility, dramatically faster and more accurate tag detections, support for ARToolkit-style markers, and the ability to fix the camera focus.

### 1.0 — 2013-11-20

No release notes.

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| --- | --- | --- | --- |
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## More apps by Edwin Olson

- [TappaTappa](https://appshunter.io/ios/app/tappatappa/id6479014920)
- [tunatuna](https://appshunter.io/ios/app/tunatuna/id6636465759)
- [rideslug](https://appshunter.io/ios/app/rideslug/id6757870313)
- [DitDit](https://appshunter.io/ios/app/ditdit/id6759913757)

All apps by Edwin Olson: https://appshunter.io/developer/736108131

## Related topics

[edwin olson](https://appshunter.io/ios/topics/edwin-olson) · [apriltag](https://appshunter.io/ios/topics/apriltag)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-03.*